CorrelationMatrix

class pulser.backend.CorrelationMatrix(*, evaluation_times=None, one_state=None, tag_suffix=None, default_aggregation_method=AggregationMethod.MEAN)

Bases: Observable

Stores the correlation matrix for the current state.

The correlation matrix is calculated as [[<φ(t)|n_i n_j|φ(t)> for j in qubits] for i in qubits] where n_k = |one_state><one_state|.

Parameters:

  • evaluation_times (Sequence[float] | None, default: None) – The relative times at which to compute the correlation matrix. If left as None, uses the default_evaluation_times of the backend’s EmulationConfig.

  • one_state (Literal['u', 'd', 'r', 'g', 'h', 'x'] | Literal['0', '1'] | None, default: None) – The eigenstate to measure the population of in the correlation matrix. Can be left undefined if the state’s eigenstates form a known eigenbasis with a defined “one state”.

  • tag_suffix (str | None, default: None) – An optional suffix to append to the tag. Needed if multiple instances of the same observable are given to the same EmulationConfig.

  • default_aggregation_method (AggregationMethod, default: <AggregationMethod.MEAN: 2>) – How to combine the values of this observable from multiple results.

Attributes

default_aggregation_method

How the values from multiple results are combined.

tag

Label for the observable, used to index the Results object.

uuid

A universal unique identifier for this instance.

evaluation_times

Methods

apply

Calculates the observable to store in the Results.

Signatures

apply(*, state, hamiltonian, **kwargs)

Calculates the observable to store in the Results.

Return type:

list[list]

property default_aggregation_method: AggregationMethod

How the values from multiple results are combined.

property tag: str

Label for the observable, used to index the Results object.

Within a Results instance, all computed observables must have different tags.

Returns:

The tag of the observable.

property uuid: UUID

A universal unique identifier for this instance.